Booth joined the Exiles in 2002 as assistant academy manager, graduating to responsibilities for the first team's scrum and lineout two years later. A role as forwards coach followed a year later as he continued to show willing invention and alongside head coach Brian Smith he oversaw a major upturn in fortunes for the side. When Smith joined the England setup in 2008 Booth was promoted to head coach, calling former England international Mike Catt in as his assistant in a player-coach capacity. In his first year in charge the Exiles made the Premiership final, losing out to Leicester by a single point. Booth also coached the England Saxons' forwards to Churchill Cup success in 2008.